The long term objective of this research program is to determine how the brain regulates feminine sexual behavior in laboratory animals. Since this behavior is influenced by ovarian hormones acting in specific brain regions, experimentation focuses on the mechanism of hormone action at these specific brain sites. This research program utilizes chemical stimulation of the brain to determine the potential influence of specific brain receptors, assay procedures to measure endogenous changes in putative neurotransmitter systems and analysis of brain extracts to determine endogenous brain factors that control feminine sexual responses.